Safety construction for luminous wall furnace



A. F. HOLDEN Nov. 14, 1961 SAFETY CONSTRUCTION FOR LUMINOUS WALL FURNACE Filed Aug. 3, 1959 UW GAS-All? m. m m w.

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114.07, Zei, HZ/La? 1 United States Patent() 3,008,513 SAFETY CONSTRUCTION FOR LUMINOUS WALL FURNACE Artemas F. Holden, 2195 S. Milford, R.R. 1,

' Milford, Mich. Filed Aug. 3, 1959, Ser. No. 831,096 Claims. (Cl. 158-7) This invention relates to improvements in a luminous wall furnace construction of the type disclosed in my prior Patent No. 2,828,813 and more particularly to means for improving the safety and durability of furnace installations of such type.

As disclosed in my earlier patent, the luminous wall furnaces under consideration employ a light porous firebrick, which may be in the order of 21/2 to 9 inches thick with drilled passages extending from a plenum chamber at the outer surface to within approximately l to lVz inches of the inner firing face, and through which a combu'stible vgas-air mixture permeates to the firing face where it is ignited and burned causing the firing face to become luminous and highly radiant for efficient and rapid heating of work loads within the furnace. The gas-air mixture flowing through the porous rebrick cools the brick in the areas communicating with the plenum chamber substantially below the combustion temperature, while the firing face may obtain temperatures in the order of 1000 to 2400 degrees-Fahrenheit.

In industrial furnaces having firing panels of substantiallength, the high temperature of the firing face rela- .tive -to the remainder of the tire/brick, plenum chamber and retaining framework results in a tendency for the firing face portion of the furnace wall to expand without corresponding expansion of the remaining furnace structure, which, in the absence of provisions disclosed herein, may result in substantial compression and restriction of the porosity of the iirebrick immediately adjacent the firing surface thereby reducing the capacity of the furnace for a given pressure of the fuel supply and leading to progressive cracking and deterioration of the mortar between the bricks as well as the rebricks themselves. After many cycles of heating and cooling, such cracking and deterioration may eventually result in the opening of direct leak paths between the plenum chamber and firing surface with consequent danger of flash back into the plenum chamber causing a furnace explosion.

Another source of potential danger in the operation of such furnaces has been found in the rebrick -area at the mragins bordering the firing face where the lack of flow of gas-air mixture with its cooling effect may permit back heating and/or leakage of an unburned explosive gas-air mixture.

The present invention is directed to substantially obviate these difliculties by providing expansible impervious heat resistant joints or gaskets at suitable intervals along the length of the firewall within the mortar between the bricks, between the bricks and retaining metal structural members, and/ or between adjacent metal structural members. A preferred material found eminently suitable for this purpose is a sandwich consisting of thin aluminum foil, in the order of 3/1000 to 5%[000 of an inch thick, surrounding a compressible asbestos ller or equivalent material such as `silica alumina fibre in the order of 1/32 -to 1/8 of an inch thick, which may be joined to the aluminum foil with a cement or preferably with sodium silicate.

Such la resilient joint may extend through the entire firebrick furnace wall and should extend from the firing surface back substantially in excess of 2 inches. ring the furnace at high temperatures, the aluminum foil immediately adjacent the firing surface, and backward therefrom for a distance of as much as 2 inches, is converted to aluminum oxide while the balance of the ICC aluminum foil remains intact as originally installed. For operating temperatures in the `order of 2400 degrees, such gasket material is preferably incorporated at 2 foot intervals.

In order to assure against any leakage of explosive gas mixture at the perimeter of the firing wall, a separate Upon air passage is provided around the perimeter o-f the plenum chamber from which air without gas is continuously fed through firewall brick bordering the perimeter of the firing area of the ring face. A layer of gasket material i'sy preferably incorporated between the firing and air cooled brick.

The objects and advantages of such safety construction features may be better understood from the following detailed description of a specific preferred embodiment illustrated in the drawings wherein:

FIGURE 1 is a plan view of a typical luminous furnace floor structure;

FIGURE 2 is an enlarged fragmentary sectional side elevation taken along the line 2-2 of FIGURE l;

FIGURE 3 is an enlarged fragmentary sectional end elevation taken along the line 3-3 of FIGURE 1; and

FIGURE 4 is an enlarged sectional view of a typical sandwich gasket material employed as sealing and expansion joint.

The floor structure consists of a series of panels mounted on transverse channel legs 10 welded to vertical side plates 11 and separated by sealing gasket material 12. Solid transverse horizontal plates 13 welded tothe channel leg members 10 form the bottom of plenum chambers 14 while perforated upper plates 15 welded to the side plates 11 support the lirebrick 16 of the furnace.

A gas-air mixture supplied to the plenum chambers 14 by suitable inlet connections, not shown, ows through the passages 17 and the porous iirebriek 16 to the firing face 18 at which the gas burns creating a luminous radiant heating surface. Cooling air passages 19 are provided around the perimeter of each of the plenum chambers 14 feeding cooling air through the passages of the porous rebrick to the outer surface 20 around the perimeter of the firing face 18. The inner face 18 of each panel thus consists of a iired area sur-rounded by a nonred area. Gasket material 21 similar to the gasket material 12 and illustrated in FIGURE 4 is employed between the adjacent fired and air cooled brick, to form an effective seal and expansion joint, and at intervals between the fired brick also. Such gasket material preferably comprises a sandwich of aluminum foil 22 bonded to an asbestos core 23 with sodium silicate. The core may be in the order of 1/,2 to l/g of an inch in thickness while the aluminum foil may be in the order of ooo to 5/1000 of `au inch thick.

While a preferred embodiment has been disclosed and described above in detail, it will be understood that numerous modifications might be resorted to without departing from the scope of this invention as defined in the following claims.

I claim:

1. A luminous Wall yfurnace comprising a furnace framework, a porous iirebrick furnace wall extending within said framework, a limited first portion of said wall spaced from said framework having an interior firing face, a combustible gaseair mixture plenum chamber communicating with the exterior portion of said wall corresponding to said firing face, means for supplying a combustible gas-air mixture thereto, gas impervious barrier means in said -wall extending along the margin of said first portion confining the flow of gas-air mixture from said plenum chamber thro-ugh said porous iirebrick wall to said firing face, a second portion of said porous firebrick furnace wall extending around the perimeter of said firing face between said barrier means and said frame- 3 work, an rair chamber" adjacent'said'plenum chmberfor supplying cooling air through said second portion to its interior face vextendingalong the margin of said firing face.

Vside of an asbestos core.

4. A furnace construction as set forth in claim 2 wherein said gasket material comprises a sandwich of aluminum foil on either side of an asbestos core and including means for bonding said aluminum foil to said asbestos core.

5. A furnace as set forth in claim 4 wherein said lmeans for bonding comprises sodium silicate.

6. A furnace as set forth in claim 2 including spaced metal structural elements supporting and dividing said rebrick wall into panels, said gasket means being also included as a sealing element between said spaced metal structural elements.

7. A luminous wall furnace as set forth in claim 1 wherein said second portion comprises at least one row of porous rebrick surrounding said first portion, and wherein said gasket means is interposed between all adjacent surfaces of said first and second portions.

8. A heating panel for a luminous wall furnace of the type wherein a combustible gas-air mixture is fed through porous rebrick to ignite and burn on the inner surface thereof, said panel comprising metal frame members defining themargins' thereof,n a plenum rvchamber-*including la perforated metal member extending between said frame members forming the inner wall of said plenum chamber, porous firebrick mounted on Said plenum chamber inner wall between said frame members, gas impervious barrier means deiiningan'd separating a luminous tiring area.V on the inner surface' of said irebrick communicating with said plenum chamber from a nonring second portion of air-cooled porous 'firebrick surrounding the perimeter of said firing face, means for supplying a combusti-ble gas-air mixture to said plenum Y chamber, and an air chamber adjacent saidl plenum charnber for supplying cooling air to said non-firing perimeter.

9. A heating panel according to claim 8 whereinsaid gas impervious barrier means comprises resilient gasket means between said porous firebriok of the firing area and non-firing perimeter.

l10. A heating panel according to claim 9 further characterized by gasket means interposed between adjacent rebrick across said tiring area,

References Cited in the file of this patent UNITED STATES PATENTS 1,074,110 Fyfe Sept. 30, 1913 1,225,381 Wedge May 8, 1917 1,304,755 Ellis May 27, 1919 1,532,260 Osthoff Apr. 7, 1925 1,883,983 Lanyon Oct. 25,4 1932 1,927,859 Wald Sept. 26, 1933 1,940,350 Hautz ..Dec. '19, 1933 2,311,350 Richardson Feo-16,` 1943 2,828,813 Holden Apr. 1, 1958 FOREIGN PATENTS 477,958 France Aug. 21, 1915 

